1. Technical Field
The present invention relates to a display device having a function of performing display in response to a direct input and to an electric paper.
2. Related Art
In recent years, display devices using various electro-optic materials such as liquid crystal materials or electrophoretic materials have been provided.
Further, in the past, a digitizing tablet (a digitizing device) for a display panel (a display device) using, for example, a light emitting diode has been proposed (see, e.g., JP-A-2003-223272). It should be noted that as the digitizing device some types are known, as disclosed in the document mentioned above as related art.
A digitizing device is arranged to allow the user to directly input data on a lattice by writing a character or a diagram, or designating a position of a stylus on a digitizer array. Specifically, such types as described below are known.
1. A type of making a tip portion of a stylus have a direct contact with a capacitive-resistive array.
2. A type of allowing the user to input data, and using an electromagnetic digitizer interacting with a stylus having a magnetic tip structure or an electromagnetic field generating stylus when performing a desired operation.
3. A type formed of a stylus equipped with an RF transmitter for transmitting a signal to a digitizing array.
4. A type having a light source built-in, such as a visible light source or an infrared light source disposed inside a tip of a stylus so that the light is reflected by a pad.
Such a digitizing device is directly provided to a monitor as a display device, or separately provided from the monitor. In general, the digitizing device requiring a larger working surface compared to the size of the display device is provided separately from the display device, or in the case in which portability or compactness is required, the digitizing device is directly built into the display device to form an integrated digitizing device.
Incidentally, in the digitizing device or the display device equipped integrally with the digitizing device described above, it is difficult, in principle, to correspond to upsizing thereof because the processing speed is proportional to the performance of a processor, and further, it is also difficult to achieve low power consumption because the power is also required in the standby state. Further, there is a demand for capability of displaying an underline or a note on a display screen by directly inputting them on the display screen in addition to the original display function, and in that case, there is a further demand of performing a gray-scale representation in the display by the direct input.